Dog Spay/Neuter: Does Age Affect Likelihood of Weight Gain?


Home / Dog Spay/Neuter: Does Age Affect Likelihood of Weight Gain?
veterinary exam for dog health

Regular veterinary visits help owners manage their dog’s weight. Photo credit: US Military

Obesity is becoming a serious problem, not only for people, but also for their pets.  One area of concern has been whether the age at neutering/spaying has any health implications for dogs, including the tendency to gain weight.

A 2013 retrospective study did find that spay/neuter increased the risk of dogs becoming overweight. The study also lead to two other important conclusions:

  • Early spay/neuter (at 6 months or younger) does not increase the risk of weight gain.
  • Careful attention to weight management in the first two years after surgery can reduce the risk of dogs gaining excessive weight throughout the dog’s life.

The Value of Spay/Neuter for the Individual Dog and Owner

Reproductively active dogs, both male and female, create challenges for the average dog owner. The drive to reproduce causes both males and females to attempt to escape the confines of their normally acceptable life, increasing the risk of injury while roaming unsupervised.  Add in the stray dog problem nearly everywhere and, for most dog owners, the sensible choice is to have their pet neutered.

Spaying/neutering has, however, long been linked with weight gain in pet dogs. As our knowledge of the negative effects of obesity increases, dog owners may be tempted to avoid spaying/neutering for the potential health benefits of lower risk of weight gain. A retrospective study of neutered/spayed dogs seen at Banfield Pet Hospitals indicates that weight gain is not an unavoidable outcome of the surgical procedure.

Age When Surgery Occurs May Not be a Factor in Weight Gain

For proponents of early spay/neuter, the findings of this study are positive. Many dogs adopted from shelters, despite new owners being offered free or discounted spay/neuter surgery, remain intact and contribute to the pet overpopulation problem. Spay/neuter performed before a dog leaves the shelter eliminates that problem,xcdz but there has been ongoing concern regarding possible negative health consequences. Weight gain or even obesity is one of the potential problems cited by those who feel that early spay/neuter needs further investigation.

Link between dog obesity and diet

Feeding a balanced diet is necessary to reduce the risk of obesity in dogs. Photo credit: Jason Meredith

The results of the study by the Banfield Applied Research and Knowledge (BARK) program suggest that there is a critical window of two years during which dogs are prone to becoming overweight. The reasons for the weight gain were not identified in this study, but possibilities include feeding higher energy puppy food beyond the point where it was necessary, and slower metabolism after surgery.

Obesity in Dogs: The Right Diet and Regular Exercise Works for Dogs Too

Dogs are often fed quantities based on pet food manufacturers’ recommendations. Some dogs will do well on the recommended amount, while others may need more or less food, and the age at which a dog should be changed over to adult food will vary based on breed, size and individual activity level.

In an interview with Dr. Sandi Lefebvre, lead author on the BARK study, Decoded Science learned that helping owners create an appropriate diet for their dog reduces the risk of weight gain after spay/neuter surgery. Dr. Lefebvre told Decoded Science:
A little experimentation might be necessary to determine whether the amount suggested on a food bag or can—which sometimes can be a “one size fits all” instruction—is indeed appropriate for an individual dog.”

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